The Himalaya Mountains are a biodiversity hotspot, boasting one of the world’s richest insect biotas. However, the primary mechanisms driving such high mountain biodiversity remain unclear. To address this, we use Scymnus, the largest genus of ladybirds, to explore the biogeographic origin and spatiotemporal evolution of the eastern Himalayan insect fauna for understanding the biological response to orogenic movement. Combining mitochondrial genomes and two nuclear genes (18S and 28S), we reconstructed the first highly supported and dated backbone phylogeny of Scymnus. Our findings strongly support the monophyly of Scymnus and identify seven major lineages within the genus. However, the subgenus Scymnus, Orthoscymnus and Pullus were found to be polyphyletic. We conclude that most extant Himalayan species originated through in situ speciation, with the Himalayan Scymnus lineage originating during the late Eocene and undergoing rapid diversification in the early Miocene. This diversification was likely triggered by the rapid uplift of the Himalayas and aligns with the recently proposed stepwise hypothesis of Himalayan orogenesis. Our findings, combined with net diversification rate analysis, indicate that new niche opportunities created by mountain uplift govern the diversification of the genus Scymnus. Furthermore, we found that the significantly higher diversity of Scymnus in mountains regions is driven by a combination of ecological factors, primarily the intensification of the Asian monsoon during the Miocene, which further strengthened the diversification of Scymnus in Himalayas. Our study provides a framework for biogeographic and evolutionary studies in eastern Himalayan Mountains, contributing to the understanding of the mechanism underlying.

A limited understanding of the feeding habits of ecosystem service providers is a notable obstacle to the deployment of natural enemies in pest management. Understanding the dietary diversity of predators can enhance conservation strategies and assess their effects on pest populations. In this study, we used metabarcoding of DNA extracted from the gut contents of an artificially released generalist predator, Eocanthecona furcellata, collected from tobacco cultivation fields in Yunnan Province, China. We aimed to investigate prey composition, selectivity, and efficiency of biological control. Among the 253 individuals of E. furcellata, we detected diverse potential prey, comprising 53 insect species across 28 families and seven orders. Several agricultural pests, including Spodoptera exigua, S. litura, Helicoverpa armigera, and Agrotis segetum, were identified. Diptera are important in the diet of E. furcellata, with 22 species from 14 families accounting for 52.2% of the observed predation events. E. furcellata consumed certain beneficial predators present in the tobacco fields, such as carabid beetles, hoverflies, wasps, and lacewings, although the incidence was generally low, except for Syrphidae. Our findings revealed previously unidentified trophic linkages involving E. furcellata with pest species and other biological control agents, as well as with neutral insects in tobacco fields. These insights contribute to the development of targeted biological control programs to manage key pests in this agroecosystem. This study establishes an important foundation for integrating metabarcoding technology into biological control research, particularly for elucidating trophic interactions between natural insect enemies, piercing-sucking mouthparts, and their prey.